Threaded casting



'provided with said improvement.

lhvirnn STA-TES PATENT rricn. 4 1

JOHN B. LARKIN, or PITTsU'RfG, PEN,Nsvnvnnrrnv THR-EADED'OASTING.

SPECIFICATION formingpart of Letters Patent-No. 294,639, dated March 4, 1884.

Application filed June 4, 1883. (No model.)

To all whom it may concern/r Be it known that I, JOHN B. yLARKIN, of Pittsburg, in the countyv of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Threaded Castings, and I do hereby declare that the following is a full, clear, and vexact description of the invention, which will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, which form a part of this specification, in which- Figure l is a sectional view of a casting of a water-back having my improvement applied. Fig. 2 is a side view of a sheet=metal thimble. Fig. 3 is a sectional view of an elbow-joint to which my improvement is applied; and Fig. 4. is a vmutilated. side view of a hydrant-spout y Fig. 5 is a plan of one-half .a molding-askjhaving the pattern imprint and the core and thimbles in place therein.V

This invention relates to the casting of articles which are to be used with screw-threaded attachments requiring the casting to be bored out and threaded before it can-be put to use. Am ong such articles may be mentioned, as illustrations, water-heaters, pipe-elbows, flangeunions, reducers, globe-valves, faucets, and many others. lThe boring and threading of these and other similar articles after casting is troublesome and costly. y

Among manufacturers of such hollow castings as are intended for use under fluid-pressure, it is a general practice to test the casting for shrinkage-cracks, sand-holes, blow-holes, and other imperfections which would impair its usefulness and perhaps prove a source of danger. To make the test, the custom is to cast or bore two holes in the casting-walls, true them, and then tap them for pipe-fittings,

after which inlet and outlet pipes are attached, Vand steam or water pressure admitted, Whose leakage will detect the imperfection, if any exist. But this boring and tapping process is uniform thickness throughout.

.vention can be made in this way.

sand, is ready for coupling on the test-pipes,

or for actual use without further manipulation.

This invention consists ina metal casting having in combination therewith a threaded sheet-metal thimbl'e having its threads struck up or spun, embedded therein or thereon by pouring .the casting metal around or into the said thimble.

A simple illustration of my invention is found in an ordinary Water-back for obtaininga supply of hotwater from kitchen stoves and ranges. Such castings are especially required to be sound and perfect throughout, and

every one made is thoroughly'tested. Before pouring the metal forsuch a casting as the Water-back A, I place in .the mold the prepared thimbles b, which are of sheet metal and suitably threaded to standard pipe-ttings, by spinning or striking up the thread, thus leaving the `thimble of a substantially I then pour the metal, which welds around and upon the thimbles, so that after cleaning out the casting can be at once tested for imperfections without any further manipulation.

The -thimbles b are struck up or spun out of sheetvmetal, and the welding takes place readily, and even if slightly imperfect will be vsufficiently calked up by the insertion of the pipe.. The thimbles b may be male or female, the results being the same in both cases.

The invention is` equally applicable to all castings which ordinarily require lto be bored and threaded. l

Fig. 3 shows an ordinary elbow having two thimbles, b, as illustrated, enlarged, at Fig. 2, the thimbles being both female. Fig. 4 shows a male thimble applied after my invention to a hydrant-spout.

A great variety of applications of my in- I have illustrated only a few of them. Others will readily suggest themselves to the skilled mechanic. l do not therefore limit the scope of my invention to any particular article or line of articles.

The thimbles are of thinsheet metal, in order to be capable of being struck up or spun with threads, and being thin they readily assume the heat of the molten metal withoutf IOO In testimony that I claim the foregoing as my'oWn I have hereto aHXed my signature 1n presence of two witnesses.

JOHN B. LARKIN.

Vitnesses:

T. J. MCTIGHE, T. J.` PATTERSON. 

